PHOENIX (KPHO) – May 4, 2012 – Crime scene investigators combed for clues around a Phoenix apartment complex Friday, looking for anything that will help track down a violent sexual predator who police said raped and tortured a woman throughout the night.

Carli Patterson lives next door to the 56-year-old victim in the complex at Seventh Street and Indian School road.

Patterson told CBS5 that she heard her neighbor talking at about 3 a.m., but simply thought she had company.

Patterson said she had no idea what had happened until about 8 a.m., when someone knocked on her neighbor’s door.

“When she yelled for help, I opened my door and she was outside, completely nude,” said Patterson. “Her hands were tied behind her back and there were two scarves around her mouth. She was gagged and tied up with bruises all over.”

The victim told police she had been tortured for hours and raped repeatedly, while being forced to drink bleach.

According to police, a cab driver had knocked on the front door to pick the victim up and take her to a scheduled doctor’s appointment.

It appears that the knock on the door scared the rapist off, police said. The suspect ran out of the apartment and hasn’t been seen since.

Police said the suspect is black, 25 to 30 years old, medium height and build, shoulder-length dreadlocks and wearing a baseball cap backwards, a gray T-shirt, dark shorts and flip-flops or sandals.

Detectives spent the day looking for evidence.

“Forensic evidence is a key and crucial part of solving crimes,” said Sgt. Tommy Thompson. “It ties a suspect to a scene and that’s what we’re trying to do, get information to identify this individual and bring him to justice.”

Police said they do not have any reports of similar attacks in the area and there is no indication the victim knew her attacker.

Neighbors are planning to take extra precautions when it comes to their safety.

“I’m having somebody stay here with me,” said Patterson. “You never know.”